Magnetically induced aircraft landing wheel rotation

ABSTRACT

An aircraft landing wheel assembly comprising a set of rotating components and a set of static components wherein an applied electrical current applied to conductive elements associated with one set of components gives rise to primary magnetic fields which interact with reactive magnetic fields associated with the other set of components whereby the interaction of magnetic field forces gives rise to rotational forces which act on the rotating components of said aircraft landing wheel assembly to induce controlled forward rotation of the landing wheel prior to contact with the runway and controlled retardation assistance as required during deceleration of the aircraft after touch down with the runway.

BACKGROUND OF THE INVENTION

An Information Disclosure Statement is enclosed along with a fulldescription of Prior Australian and P.C.T. Patent Applications by theInventor of this present Invention.

FIELD OF THE INVENTION

The present invention relates to an aircraft landing wheel rotatingapparatus specifically designed to achieve controlled forward rotationof the main landing wheels of large commercial, and cargo aircraft priorto touch down with the runway thereby reducing wear on tires reducingimpact loadings on the landing wheel assembly, reducing the possibilityof sudden tire blowout. Improving aircraft stability at touch down byreducing differential torque reaction due to the fact that not allwheels impact the runway together and potentially improving brakeefficiency by providing the option of a degree of retardation assistanceafter touch down during the deceleration of the aircraft while braking.

DESCRIPTION OF THE PRIOR ART

Aircraft wheel rotation devices or pre-rotation devices are widely knownin the prior art of up to 50 years or more in the past.

The extensive interest shown by inventors both past and presenthighlights the potential importance of a system which overcomes theshort falls of the prior art.

Aircraft landing wheel rotation devices forming the majority of theprior art have been developed for the fulfillment of countlessobjectives and requirements.

By way of example an international search report conducted by I.P.Australia returned Category A, documents defining the general state ofthe art which were not considered to be of particular relevance. Thesebeing the foreign patent (MERLAKU) 20 May 1999, GB2311264A (TOON.ET.AL.)24 Sep. 1997 certified copies of which are enclosed as part of theInformation Disclosure Statement along with relevant translations.

It should be noted that the present invention was previously lodged asan Australian Patent Application AU2004237817, 9 Dec. 2004, Improvementsin Aircraft Landing Gear which claimed priority of a ProvisionalSpecification Number 2003906883, 15 Dec. 2003 Improvements in AircraftLanding Gear, The Australian Patent Application was published by I.P.Australia on 30 Jun. 2005 less than one year prior to which the sameinventor lodged this U.S. patent application. As regards the U.S.application the dates of the Australian Patent Applications should beconsidered in the case of a first to invent ruling. A P.C.T. applicationdescribing this present invention was lodged by this inventor with I.P.Australia on the 24 Oct. 2005.

Copies of the P.C.T. and Australian Patent Applications are enclosedalong with the P.C.T. International Search Report which cited AU2004237817 A1 (SODERBERG) 30 Jun. 2005 as the only document cited whichwas of particular relevance to the novelty of the P.C.T. applicationhighlighting the unique features of the present invention which is in noway influenced by the Publication by I.P. Australia 30 Jun. 2005 sincethe present invention has been lodged with the U.S.P.T.O. within therequisite 1 year period and no other discloser or issuance of patent orinventors certificates have been performed. Two of the InternationalSearch Report cited patent applications DE29900944U1 (MERLAKU) 1999 andGB2311264A (TOON.ET.AL) 1997 mention the use of small electric motors.GB 2311264A (TOON.ET.AL) shows a remote mounted proprietary type ofelectric motor driving the aircraft wheel through either a shaft driveor friction drive on the tire while DE 29900944 U1(MERLAKU) simply makesmention of a small electric motor. Neither system was considered by theInternational Search Report as being considered of particular relevanceand neither is likely to be feasible in the crowded landing wheelassembly of modern day commercial aircraft for which the presentinvention is designed. An inspection of FIG. 3 of the Drawingsassociated with the present invention shows a wheel and brake assemblytypical of the main load bearing landing wheel assembly found on thepresent day commercial, cargo, and all heavy duty fixed wing aircraft.It is clearly seen that there is extremely little free space in any ofthe main landing wheel assembly, incorporating a brake stack within thewheel along with the brake actuating mechanism and wheel supportstructure leave little or no free space for mounting a small proprietaryelectric motor.

Also pertaining to the prior art are an array of U.S. Patents

U.S. Pat No. 5,746,393 Gennaro discloses an Aircraft Wheel RotatingApparatus.

U.S. Pat No. 5,165,624 Lewis discloses an Apparatus for pre-rotatingaircraft wheels employing forced air and a vacuum.

U.S. Pat No. 4,491,288, Sinclair discloses and Aircraft landing wheelrotating means.

U.S. Pat No. 5,104,063 Hartley discloses an Aircraft landing gearpre-rotating system.

The respective U.S. Patents listed also list an array of similar U.S.Patent applications all directly related to pre-rotation of aircraftlanding wheels prior to touch down.

While the majority of these devices fulfill their respective objectivesthe previously mentioned patents differ considerably from the principlesand mode of operation of the present invention.

Few if any of the inventions associated with the prior art address whatis claimed to be a significant problem associated with pre-rotation ofaircraft landing wheels, this being either increased landing distance orincreased brake loadings due to the loss of an amount of retardationenergy that would otherwise be applied to the aircraft as a result ofthe energy dissipated during tire skidding and momentum transferred toachieve wheel rotation upon touch down.

This is a valid argument against pre-rotation of aircraft wheels sinceevery increment of stopping distance can be critical in an emergencysituation.

The present invention addresses this problem by providing retardationassistance as required and will have the potential to input greaterretardation assistance over the deceleration distance of the aircraftthan would have been the lost deceleration energy associated withbringing the non rotating landing wheel up to speed.

In addition to providing the option of retardation assistance and thusovercoming a claimed major draw back associated with pre-rotation ofaircraft landing wheels the present application deviates significantlyfrom the prior art by providing a mechanism for pre-rotation which iscontained within the basic structure of the landing wheel assembly thusallowing use with the crowded inner wheel situation associated withlarge commercial aircraft whereby the inner wheel region of the mainlanding wheels, with the exception of the nose wheel, is almostcompletely filled with brake stack, torque tube, and bearings, andblocked on the inner face of the wheel by the brake actuating mechanismand support structure, thus negating the practical use of many of theprior art inventions.

In addition to the previously mentioned disadvantages of the prior artit can also be seen that many of these lack the start up torque and easeof rotational speed control necessary in the situation of normal wearand tear whereby binding and friction drag of some components of theaircraft wheel assembly is inevitable and can vary from one wheel toanother and can easily be overcome by the mode of operation of thepresent invention which allows high start up torque and ease ofrotational speed modulation under conditions of variable drag andfrictional forces opposing the rotation.

The International Search Report conducted by I.P. Australia a copy ofwhich is enclosed, cited what are considered to be the most relevantpatent applications which most closely represent the general state ofthe art however these documents by PORTE, MERLAKU, TOON.ET.AL which werepreviously listed are classified as prior art references Category A,defining the general state of the art which were not considered to be ofparticular relevance.

The International Search Report cited only one document designatedCategory X, a document of particular relevance which is in fact thisinventors own Australian Patent Application AU 2004237817A1 (SODERBERG)30 Jun. 2005, which forms the basis of this present invention thusfurther high lighting the significant difference between the presentinvention and all prior art,

SUMMARY OF THE INVENTION

In view of the foregoing disadvantages inherent in the known types ofaircraft wheel rotation or pre-rotation devices present in the prior artthe present invention offers improvements which overcome thedisadvantages and in many cases incompatibility of much of the prior artto the modern commercial airliner while at the same time potentiallyimproving safety, reducing wear and tear on the landing gear and undercarriage by reducing impact loading, and extending the life of tires,providing a degree of brake retardation assistance which when allcombined, results in significant economic savings, safety improvements,due to reduced wear and tear, and increased passenger satisfactionassociated with smoother landings, with less impact.

The present cloud of tire smoke and associated impact is non beneficialto the aircraft, the passengers or the environment at a time whenefficiency and saving is a priority thus making the present invention abenefit to society in general.

OBJECTIVES, ADVANTAGES, MODE OF OPERATION

Although prior systems concern themselves with seeking the reduction intire wear and impact loadings by causing the rotation of the aircraftlanding wheels to commence prior the aircrafts actual landing, thepresent invention incorporates and utilizes a unique combination ofcomponents as well as design features which provide unique results andadditional beneficial results here to fore unavailable from prior artdevices especially when considered in relation to the present generationof Commercial and Cargo aircraft.

It is the object of this invention to create a new and unique system forpre-rotation of aircraft landing wheels which provides the additionalbenefits of retardation assistance as a result of the imposition of anelectrical current applied to specific components of the landing wheelassembly which gives rise to magnetic field forces which interact withreactive magnetic field forces associated with other components withinthe landing wheel assembly thus giving rise to rotational torque forcesand the associated benefits of reduced tire wear and impact loading dueto the rotational torque forces allowing controlled pre-rotation of thelanding wheels to match the speed of the aircraft at touch down afterwhich the benefits of retardation assistance, or regenerative brakeassistance is achieved by the same commonly available circuitry andcontrol units as allow the precise control and monitoring of the forwardpre-rotation of the landing wheels.

A micro processor link between the aircrafts own computer systemmonitoring air speed and the A.B.S. brake system, sensors, and circuitrycommonly found on most commercial aircraft with an additional link tothe electric brake actuation circuitry if used on the aircraft can allowprecise speed control of the individual landing wheel pre-rotation justprior to landing along with precise control of the brake retardationassistance after touch down.

The microprocessors, electrical control units and exact circuitryrequired do not form part of this invention, all these components andrelevant know how are widely available in the market place whichincludes a vast array of constantly improving technology associated withcontrol units and electric drive technology and drive systems,components of which can be directly applied to manufacture and operatethe present invention.

The intention of the present invention is to make use of existing andfuture developments and advances in the theory and principles ofelectric drive mechanisms, present and future technology in conductormaterials, present and future technology in the field of permanentmagnets and present and future technology in the field of electricconductor materials which give rise to strong magnetic field forcesalong with electrical control units and micro processors. All of thistechnology is available in the market place and components of thetechnology necessary to manufacture the present invention are easilyavailable with improvements in materials and technology continuallycoming onto the market.

The present invention makes use of existing electric drive system theoryand component technology and arranges these components so as to form anew and unique device which can be easily manufactured by personsskilled in the art and can make use of both present and future materialsand technology to upgrade and improve the efficiency of the inventionwhile maintaining the basic mode and principles of operation of thepresent invention.

The primary characteristics of the present invention which separate itin terms of novelty and inventiveness from all other prior art resultsin part from the method of housing the drive system, which is designedspecifically to achieve pre-rotation and retardation assistance of themain load bearing aircraft landing wheels of large commercial airlinerswherein the inner wheel is virtually completely filled with brake stackand the inner face of the wheel is almost completely blocked by thebrake actuating mechanism, torque tube, and the support structure towhich the torque tube and the total assembly is attached. Inspection ofFIG. 3 of the drawings clearly shows the space limitations associatedwith a typical aircraft main landing wheel assembly.

The present invention overcomes the problem of space by making theindividual components of the drive system a part of the componentstructure of both the static and rotating components of the aircraftlanding wheel assembly which forms the housing for the drive componentsand in so doing totally separates the present invention from all priorart. The ability to also provide a significant and useful amount ofretardation assistance or regenerative braking is the result of the hightorque characteristics that can be achieved by this present inventionand is an added benefit over prior art.

The present invention differs greatly from all prior art in the mode andmethod of operation and construction and provides a new and improvedmethod of pre-rotation and brake retardation assistance for the mainlanding wheels of commercial, cargo, and other aircraft which is unique,novel and has significant industrial applicability and benefits.

DESCRIPTION OF THE DRAWINGS

FIG. 1 of the drawings shows the rotating wheel and hub assembly of theAircraft landing wheel assembly,

FIG. 2 show the brake stack assembly of housing, rotors and stators andbrake actuating mechanism,

FIG. 3 shows the combined assembly of the aircraft landing wheelassembly.

The drawings enclosed, FIGS. 1, 2 and 3, show sections of the maincomponents that make up the aircraft landing wheel assembly and inparticular the set of static components of the brake actuation mechanism3 the Brake Stack Housing 4 and internal stators 2 an assembly whichtransfers load to the torque tube and strut of the landing gear all ofwhich represent static components.

The set of primary rotating components associated with the aircraftlanding wheel assembly are the rotors 1 the inner wheel section 15, theouter wheel section 16, and the wheel hub assembly 17.

The Brake Stack consists of rotors 1 which are keyed to the aircraftswheel and rotate with the wheel and stators which are keyed to thestationary torque tube, which is part of the landing gear structureotherwise known as the aircraft landing wheel assembly, which reacts totorsion and axial loads generated during braking.

Rotors 1 and stators 2 are circular disks made of carbon composite orsteel which collectively form a cylinder within the brake stack housing4 otherwise known as heat stack housing 4.

Electrically conductive elements in the form of field windings, or coilsor electrically conductive material which give rise to magnetic fieldswhen subjected to an electric current are attached to one set ofcomponents either the static or rotating components and form the primarymagnetic field components.

The other adjacent set of components house reactive or secondarymagnetic field forces which are created by either permanently magneticmaterial or by conductive elements in the form of suitable magneticallysoft material or suitable magnetically soft material enhanced byinduction field windings otherwise known as induction coil windings inwhich magnetic fields are induced by the primary magnetic field.

The locations of adjacent sets of primary magnetic field components andreactive or secondary magnetic field components are shown in locations 5to 14 inclusive on FIGS. 1, 2 and 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to improvements in aircraft landing wheelassembly. These improvements relate specifically to controlling theforward rolling speed of the wheel and tire assembly prior to landingand where required applying added retardation to the wheel afterlanding.

The aim is to adjust the wheel and tire assemblies forward rotationalspeed prior to landing so as to reduce tire skidding, reduce impactloading on the landing gear, reduce tire wear, thus reducing the chanceof sudden tire failure and reducing impact wear and tear on wheels andlanding gear. Safety is potentially improved and maintenance costsreduced.

The objective of the system is to precisely control the forwardrotational speed of the aircraft landing wheel-tire in relation to theground speed just prior to landing and applying a degree of retardationassistance after touch down by means of an imposed electric currentspecifically to induce magnetic field forces located on or withincomponents of the wheel, brake assembly and components of the associatedlanding gear, such components being contained or partially containedwithin the wheel and or brake assembly and being either an attachment tosuch items or forming part of such items during manufacture.

This does not necessarily mean that all wheels will spin at a forwardrotation rate equal to ground speed at the point of tire impact with thetarmac, although this rotation speed may be optimum for some aircraft.

It may be found desirable to have the landing wheels and thus tyresspinning at a rate either faster, equal to or slower than the rotationrate equivalent to ground speed of the rolling tire.

The optimum rotation speed of the aircraft wheels just prior to landingwill be determined by the type of aircraft, the runway pavementcondition, dry, wet, icy, hot or cold, the type of pavement and frictioncharacteristics.

The optimum wheel rotation speed, for the particular aircraft and runwaypavement conditions can be adjusted to afford improved stability of theaircraft under a variety of conditions. The tire making contact with therunway can have a contact speed differential either faster, slower orequal to the actual ground speed in order to promote stability.

The ground speed of the aircraft is already accurately monitored by theaircraft instruments.

Wheel rotation rate sensors are already readily available on aircraftbrake and brake antiskid systems. These systems are easily modified toregister rotation speed which for a known tire circumference can beconverted directly to rolling speed and compared directly with groundspeed. Linking of the system to micro processing equipment can giveautomatic control of optimum wheel pre-rotation and the degree of brakeassistance utilized.

The aim is to adjust or fix the rotation rate of the landing wheelseither automatically or manually to correspond proportionally faster orslower or equal to ground speed as determined by the optimum for theparticular aircraft and pavement conditions.

A fixed wheel rotation speed set to a median speed which approximates tothe landing speed of a particular aircraft type under most conditionsmay prove satisfactory and to afford suitable benefits without thecomplexity of variable speed control.

It may also be considered that with present aircraft a certain amount ofenergy may be absorbed by the normal wheel assembly impact and tireskidding on the pavement. This energy absorption may be considered tooffer a small amount of braking to the aircraft which would not occur ifthe wheels are already spinning when pavement contact is made. Tocounteract this small loss of braking energy the system proposed willoffer the option of a form of “regenerative braking” or “reverse drive”which will assist the normal brake system of the aircraft throughout thebrake cycle thus more than offsetting the effects of wheel pre-rotationon stopping distances.

Wheel rotation is to be achieved either, electrically, orelectro-mechanically whereby an electric current will create fieldforces that induce rotation of mechanical components of the wheelassembly at a controlled or predetermined rate of rotation. The wheelassembly shown in FIG. 1 in this instance refers to the wheel rim,otherwise described as inner and outer wheel sections, and wheel hub andbearing assembly while FIG. 2 refers to the brake stack or heat stackcontaining rotors 1 and stators 2, the brake actuating components of thepiston housing 3, or electric brake actuator are specifically detailedwhile the central supporting torque tube and main strut support are notshown to avoid over complication of the drawings.

Present commercial aircraft and freight aircraft utilize a wheel, tire,axle, and brake assembly which will be referred to as the landing wheelassembly. This landing wheel assembly will be improved to incorporateelectric field coils, and or electrically excited components, which giverise to magnetic fields and or permanent magnets such that an imposedelectric current will create forward rotation of the wheel tire assemblydue to forces set up between the interaction of magnetic field forcesassociated with static and rotating components of the landing gear andwheel and brake assembly.

This system may be fully or partially contained within the wheel andbrake assembly.

The static components of the system are the strut which supports allloads including the aircraft weight, the torque tube which absorbs thetorque loads from the rotors and stators transferring these loads to thestrut., the piston housing or brake actuating components 3 and theirsupport frame plus all stators 2 and support structures and brake stackhousing 4 are static components. Either static or rotating componentscan be adapted to accommodate the primary magnetic field.

For ease of understanding of the mode of operation the static componentsshall be considered to accommodate the primary magnetic field whichresults from an imposed electric current. Transfer of electric currentto static components is easy and considered as part of the preferredembodiment. The rotating components could also receive an electricalcurrent however this would involve slip rings and brushes or commutatorsthus increasing complexity although the mode of operation is similar andshould be considered as an alternative in this invention.

The static components can be adapted to support or house the primarycircuit of the active or primary magnetic field generating medium whichin the most simplified case would be field windings on or attached toone of the static components or formed into said component.

These field windings could be formed as a plurality of individual orlinked coils around the circumference in region 7 or cylindrical fieldwindings 7 forming a thin cylindrical ring around the outercircumference of the brake piston housings 3 and induce magnetic fieldswhich impose reactive forces on opposed magnetic fields associated withcomponents attached to the inner rim of the rotating wheel assembly 11.

Alternatively primary field windings can be mounted on componentsassociated with the brake stack housing in locations 8, 9 in the form ofdisk shaped field windings and as a cylindrical form in location 10these can be axial flux air gap stator disk or cylindrical fieldwindings and may or may not contain magnetic core material whereby thefields created react with opposing magnetic fields attached to or formedinto rotating components associated with the wheel or hub in location12,13,14. Another alternative is to attach primary field windings to astator in location 5 or a prior mentioned static component of the brakestack and react with a rotor in location 6 in close proximity which ismodified to maintain magnetic fields.

In the simplest case item 11 could be high field strength rare earthmagnets bonded to, or formed into, or otherwise attached to the innerrims of the wheel interacting with field coils 7 and function as abrushless D.C. motor drive system although numerous alternative electricmotor drive systems and control units are freely available such as 3phase synchronous drive systems or brushless A.C. drive systems.

The field windings will generally be set out in an even radial patternof placement around the perimeter of the static support structure. Items12, 13, 14, can be easily formed by attaching or incorporating into thewheel component structure rare earth or similar high field strengthpermanent magnets set out in a ring disk formation as items 12 and 13 orcylindrical formation of an array of separate magnets as items 11 and14. alternatively these components could be conducting field windings ormagnetically soft segments or such segments enhanced with induction coilwindings set into the prescribed locations so as to allow an inductionfield to be set up by a primary current thus acting as an inductiondrive system which can function adequately with a suitable inverter andcontroller. Numerous drive systems are freely available along withsuitable field windings and technology.

All static components, strut, torque tube, brake piston housing 3, brakepiston support frame, brake stack housing, or one of the stators atapproximate location 5 in the brake stack can be adapted or manufacturedto incorporate or mount a primary field winding. An electric brakeactuator can be used in place of the brake piston housing withoutalteration to the basic field winding arrangement.

Field windings may take the form of a flat armature winding disc or awinding of cylindrical form which may or may not incorporate an ironlessair gap and can be attached directly to a stator in approximate location5 or the brake stack housing structure 4, torque tube or brake supportstructure, or any one or more previously mentioned static components inproximity to the rotational component with which their magnetic fieldsreact.

The radius of placement of the static field winding or flat armaturewill be dependant upon the rotating component on which the static fieldwinding will impose field forces.

Rotating components which can interact with the imposed field forces eg.permanent magnets, or magnetically ‘soft’ material have possibleplacement locations which include the inner region of the wheel inapproximate locations 11, 12, 13 the outer perimeter of the hub location14 or one or more of the rotors at approximate location 6 in the brakestack with each plurality of components forming a continuous ring. Thespecification of electric drive system to be used is open to widevariation, since there is a wide variety of electric drive systems whichwould suite the purpose.

A brushless D.C drive system with static field windings and high fluxdensity permanent magnets attached radically to and spaced around theperimeter of the rotating component is probably the simplest method ofachieving all requirements of torque, and precise rotational speedcontrol.

This is one of the layouts described in detail in this document. HoweverBrushless A.C drive system types and A.C Induction drive systems withsuitable inverter, and or micro processor control will serve thepurpose. The rotating components of the electric drive system can bepermanent magnets set around the rotating component or as a disk ormagnet ring made up of separate magnets attached to a rotor or the wheelrim or hub. Toothed blocks of magnetically soft material may replace themagnets as may induction coils or windings depending on the chosenelectric drive type to be employed. This material may be attached to orformed into the structure of the rotating component.

There is a very large array of electric drive types whereby the basicmode of operation eg. AC induction or DC brushless system or 3 phasesynchronous or a wide range of alternatives can serve as the mode ofoperation of the drive system incorporated into the aircraft wheelassembly and providing precise forward wheel speed rotation prior tolanding and the option of retardation assistance after initial touchdown and brake application.

High magnetic flux rare earth magnets such as Neodymium or SamariumCobalt are now easily available. Magnetic material and sintered magneticmaterial can be formed into complex shapes and it is quite feasible toincorporate these materials into the matrix of components such as carboncomposite rotor and stator disks during manufacture. Axial flux ironlessair gap stator windings in combination with ring disk rotors composed ofrare earth permanent magnets of Neodymium, iron and boron are gainingpopularity in high torque, high efficiency applications.

Induction motor drive theory, inverters and controllers can be utilizedto incorporate induction field windings into the matrix of stators orother previously mentioned static components or rotors thus providingboth structural reinforcement and a means of inducing magnetic fieldforces.

Sintered metal or magnetic particles can be incorporated into the matrixof rotor or stator disks to enhance the magnetic fields induced.

Primary magnetic fields can be created in field winding of virtually anyshape from flat disks, to cylindrical rings, to complex formed shapeswhich could link locations 8, 9, and 10 of FIG. 2 creating a verypowerful drive.

The field winding which gives rise to magnetic field forces does notnecessarily have to be a metallic conductor a non metallic conductorintegrated into the matrix of for instance one or more carbon compositestator or rotor disk during manufacture can under the influence of anelectric current give rise to magnetic field forces which due tointeraction with an adjacent field force associated with one or morerotors of the brake stack or a static component in proximity allow thecreation of an extremely powerful and reliable mechanism totally suitedto the harsh environment of the brake stack. A system which is highlysuited to commercial application.

For the purposes of creating a working model of the present invention ahighly efficient model can be fabricated simply by bonding an array ofthin permanent magnets into a recess around a median circumference of arotor as shown in location 6 FIG. 2 and a field winding set into arecess in a stator or end support of the brake stack in approximatelocation 5 of FIG. 2 this then acts as an axial flux design utilizing abrushless D.C. Drive System or numerous other drive systems. A workingmodel will be easily created.

Alternatively a plurality of thin neodymium rare earth magnets attachedaround a cylindrical ring extension of the inner wheel rim inapproximate location 11 and an adjacent ring of coils or field windingsset out as separate coils or a continuous winding with or without ironcore, around the perimeter of location 7 utilizing virtually anybrushless drive system from AC, to DC to 3 phase Synchronous drive toname just a few, can give rise to a high torque easily controlledmechanism which is capable of achieving the requirement of pre-rotationand retardation assistance of the aircraft landing wheel when used withthe correct drive systems and controllers.

Structural materials can be designed to provide additional performanceenhancing functions through tailoring of meso-. micro, or nanostructures. Structural materials have been termed “SyntheticMultifunctional Materials” and it is these materials which are presentlyunder development and have the capacity to give rise to primary magneticfields when energized by an electric current which form the basis ofclaim 11. In the not too distant future these materials will have theability to take the place of the ordinary electric field winding incomplex applications and should be included as a potential source ofelectrically excited material which gives rise to magnetic fields.

Sintered soft magnetic materials that can be formed to shape such assintered Permalloy or soft magnetic material manufactured by SEI can beconsidered as one of many new generation of magnetically soft materialswhich can find usage in this present invention.

SUMMARY OF PREFERRED EMBODIMENT

It should also be noted that mention is made to the incorporation ofprimary and reactive magnetic field components into the disk shaped faceof a brake stack stator or axial load retaining face at the end of thebrake stack and within the face of a rotor. A thin disk shaped fieldwinding can be recessed into the face of one or more stators or the endretaining face of the brake stack housing.

A disk shaped ring formed by a plurality of permanent magnets can alsobe set into the face of a brake rotor thus allowing the drive system tofunction as a brushless D.C. drive or a 3 phase synchronous drive systemor a multitude of other drive systems depending on the controller andelectric drive technology chosen.

Since the rotor disks are either steel or carbon composite in additionto simply recessing the necessary field windings and permanent magnetsinto the disk faces it is also feasible to incorporate these componentsinto the castings or forming during manufacture. It is also feasible toreplace the permanent magnets with sintered magnetic material duringcasting or forming or alternatively to use an A.C. induction drivesystem and replace the magnetic material with embedded coils or windingsor magnetically soft material and it is this particular embodimentassociated with modification or incorporation of the drive system withinthe housing of the brake stack which is considered by the inventor to bethe best embodiment of the invention. The alternative embodimentsdiscussed have advantages of ease of construction and can achieve hightorque characteristics due the wide radius of actuation and should alsobe considered highly viable modes of embodiment.

However the brake stack embodiments although more difficult to developdue to heat and confined space and friction surface requirements offersa very tidy solution since the whole system is self contained. Therotors and stators are normal wear items and the assembly is a regularmaintenance replacement item. Thus retrofitting a fully containedsuitably modified brake stack assembly can be considered relativelystraight forward. In addition to this commercial aircraft are subject tostringent safety requirements and any new system should be failsafe orin the instance of failure to create minimal safety hazard. Since thebrake stack and all components and modifications are fully containedwithin the inner wheel rim and the brake stack housing the consequenceof any failure or component break up is well contained thus furtherimproving the feasibility.

Brushless AC, DC, 3 Phase Synchronous drive, or a huge array of electricmotor drive theory, inverters, controllers, power and controlelectronics and new generation soft magnetic materials allow componentsof state of the art electrical machine design to be incorporated into anaircraft landing wheel assembly as described to be easily understood andconstructed by persons skilled in the field while being totally noveland unlike any other prior invention for achieving the dual benefits ofpre-rotation and retardation assistance applied to the type of aircraftlanding wheel assembly described by this invention.

The aim of the claims is not to establish a specific type of electricdrive type of which an abundant array exist. Brushless DC or AC Motors,electric drive systems with a variety of control units can adequatelyserve the purpose of inducing controlled forward rotation of theaircraft landing wheels and if necessary applying a degree of brakingretardation after landing.

The aim of the claims is to establish a means of adapting well knownelectric motor drive systems technology to form an electric drive systemspecifically designed for achieving forward rotation of aircraft landingwheels which differs markedly from any previous proposals forpre-rotation of aircraft landing wheels.

The drawings FIG. 1 and FIG. 2 of the drawing page ⅓ and ⅔ show thecomponent layout of one of a series of main landing wheels associatedwith the landing gear typically found on large passenger aircraft.

The primary components are numbered on FIGS. 1 and 2 as are thelocations of the incorporated electric drive components.

FIG. 1 shows a typical wheel, rim, hub, assembly of rotating componentswhile FIG. 2 depicts the brake stack, rotors, and stators along withpiston assembly. The pistons, mountings and housings remain stationarywhile the rotors rotate with the wheel rim and hub assembly.

FIG. 3 shows the combination of FIG. 1 and FIG. 2 which represents theassembled state of the Aircraft Landing Wheel Assembly. Reference to thefigures is made in a number of claims for clarity of description.

With respect to the above description the optimum dimensionalrelationships for the components of the invention, to include variationsin size, materials, shape, form, function and the manner of operation,assembly and use, are deemed readily apparent and obvious to one skilledin the art, and all equivalent relationships to those in the drawingsand described in the specification are intended to be encompassed by thepresent invention.

Therefore the fore going is considered as illustrative only of theprinciples of the invention. It is not desired to limit the invention tothe exact construction and operation shown and described, thus allsuitable modifications and equivalents may be considered to fall withinthe scope of the invention.

1. An aircraft landing wheel assembly such that an imposed electrical current in electrically conductive material gives rise to primary magnetic fields and such electrically conductive material is incorporated into at least one static component of the aircraft landing wheel assembly excluding stators of a brake stack, such that the primary magnetic fields associated forces interact with reactive magnetic field forces originating from material sustaining a magnetic field incorporated into rotating components of the aircraft landing wheel assembly, so excluding rotors of a brake stack as to induce rotational forces acting on rotating components creating controlled forward rotation of aircraft landing wheels prior to contact with a runway and controlled retardation assistance after touch down during deceleration of an aircraft.
 2. The aircraft landing wheel assembly of claim 1 wherein a primary magnetic field is electrically induced in a disk shaped field winding incorporated into a static housing of a brake stack and reacts with an adjacent magnetic field created by a plurality magnetic material of similar type and configuration comprised of at least one of; sintered magnetic material, sintered metal, sintered soft magnetic material, magnetic particles, permanent magnet pieces, rare earth magnets, incorporated into a wheel rim and being formed into a disk shaped ring incorporated into said wheel rim in proximity to the disk shaped field winding whereby an interaction of magnetic field forces creates rotational forces acting on rotating components of the aircraft landing wheel assembly.
 3. The aircraft landing wheel assembly of claim 1 wherein a primary magnetic field is electrically induced in a disk shaped field winding incorporated into a static housing of a brake stack and reacts with an adjacent magnetic field created by at least one of; magnetically soft material, magnetically soft material enhanced by field windings, magnetically soft segments, magnetically soft segments enhanced with induction coil windings, induction coil windings, induction coil windings enhanced by magnetic core material incorporated into at least one rotating component in which a secondary magnetic field is induced by the primary magnetic field of the disk shaped field winding whereby an interaction of magnetic field forces creates rotational forces acting on rotating components of the aircraft landing wheel assembly.
 4. The aircraft landing wheel assembly of claim 1 wherein a primary magnetic field is electrically induced within a cylindrical field winding incorporated into a static housing of a brake stack and an opposed reactive magnetic field is due to a plurality of magnetic material of similar type and configuration comprised of at least one of; sintered magnetic material, sintered metal, sintered soft magnetic material, magnetic particles, permanent magnet pieces, rare earth magnets, forming a cylinder incorporated into a wheel hub in proximity to the primary magnetic field whereby interaction of magnetic field forces creates rotational forces acting on rotating components of the aircraft landing wheel assembly.
 5. The aircraft landing wheel assembly of claim 1 wherein a primary magnetic field is electrically induced within a cylindrical field winding incorporated into a static housing of a brake stack and an opposed reactive magnetic field is due to a plurality of at least one of; magnetically soft material, magnetically soft material enhance by field windings, magnetically soft segments, magnetically soft segments enhanced with induction coil windings, induction coil windings, induction coil windings enhanced by magnetic core material, of similar type and configuration manufactured and incorporated so as to allow induction of magnetic field forces resulting from the primary magnetic field and forming a cylinder incorporated into a wheel hub in proximity to the primary magnetic field wherein induction of secondary magnetic fields results from the primary magnetic field whereby an interaction of magnetic field forces causes rotational forces acting on rotating components of the aircraft landing wheel assembly.
 6. The aircraft landing wheel assembly of claim 1 wherein a primary magnetic field is electrically induced in a series of field windings located around an outer perimeter occupied by a brake actuating mechanism and said primary magnetic field reacts with a magnetic field created by a plurality of magnetic material of similar type and configuration comprising at least one of: sintered magnetic material, sintered metal, sintered soft magnetic material, magnetic particles, permanent magnet pieces, rare earth magnets, which forms a cylindrical ring incorporated into at least one of; wheel rim, an extension to a wheel rim in proximity to the primary magnetic field whereby interaction of magnetic field forces gives rise to rotational forces acting on rotating components of the aircraft landing wheel assembly.
 7. The aircraft landing wheel assembly of claim 1 wherein a primary magnetic field is electrically induced in a series of field windings located around an outer perimeter of a brake actuating mechanism and said primary magnetic field reacts with a magnetic field created by a plurality of material of similar type and configuration comprised of at least one of; magnetically soft material, magnetically soft material enhanced by field windings, magnetically soft segments, magnetically soft segments enhanced with induction coil windings, induction coil windings, induction coil windings enhanced by magnetic core material which form a cylindrical ring incorporated into at least one of: a wheel rim, an extension to a wheel rim, in proximity to the primary magnetic field such that the primary magnetic field induces secondary reactive magnetic fields in the magnetically soft material whereby an interaction of magnetic field forces gives rise to rotational forces acting on rotating components of the aircraft landing wheel assembly.
 8. The aircraft landing wheel assembly of claim 1 wherein electrical control of components causing rotation and retardation forces within the aircraft landing wheel assembly is linked to micro processing equipment which is adapted for monitoring wheel rotation rate in relation to ground speed thereby having the ability to automatically adjust forward wheel rotation rate prior to landing and retardation assistance after landing.
 9. An aircraft landing wheel assembly comprising a set of rotating components which rotate with a wheel, excluding a brake rotor used for friction braking, and a set of static components excluding stators of a brake stack wherein static and rotating components are said to be alternate sets of components such that an applied electrical current applied to conductive material incorporated into at least one component of a set of components gives rise to primary magnetic fields which interact with reactive magnetic fields produced by material sustaining a magnetic field incorporated into at least one component of an alternate set of components whereby an interaction of magnetic field forces gives rise to rotational forces which act on rotating components of said aircraft landing wheel assembly to induce controlled forward rotation of landing wheels prior to contact with a runway and controlled retardation assistance during deceleration of an aircraft after touch down with a runway.
 10. The aircraft landing wheel assembly of claim 9 wherein a primary magnetic field is electrically induced in electrically conductive material, comprised of at least one of; a metallic conductor, a non metallic conductor, forming a field winding with at least one of; an air gap core, a magnetically soft-core, a magnetic core, incorporated into at least one rotating components of the aircraft landing wheel assembly and reacts with field forces resulting from material sustaining a magnetic field comprised of at least one of; sintered magnetic material, sintered metal, sintered soft magnetic material, magnetic particles, permanent magnet pieces, rare earth magnets, incorporated into at least one static component of the aircraft landing wheel assembly which gives rise to interacting magnetic fields whereby an interaction of magnetic fields gives rise to rotational forces acting on rotating components of the aircraft landing wheel assembly.
 11. The aircraft landing wheel assembly of claim 9 wherein electrically conductive material in which a primary magnetic field is induced comprises field windings of electrical conducting elements incorporated into at least one component of a set of components and said primary magnetic field interacts with material comprised of at least one of; magnetically soft material, magnetically soft material enhanced by field windings, magnetically soft segments, magnetically soft segments enhanced with induction coil windings, induction coil windings, induction coil windings enhanced by magnetic core material, incorporated into at least one component of an alternate set of components of the aircraft landing wheel assembly causing induction of secondary magnetic fields resulting from the primary magnetic field whereby interaction of magnetic field forces gives rise to rotational forces acting on rotating components of the aircraft landing wheel assembly.
 12. The aircraft landing wheel assembly of claim 9 wherein electrical control of components causing rotational forces and retardation assistance of an aircraft landing wheel, are linked to micro processing equipment adapted for monitoring wheel rotation rate in relation to ground speed and thereby having the ability to automatically adjust forward wheel rotation rate prior to landing and retardation assistance during deceleration after landing. 